There is an article I read that I you can customize the WordPress Administrator login. It calls for editing the HTACCESS file. I have (2) HTACCESS files, one in my root on my server and the other located with in the WordPress installation. My server does not permit me to edit or change anything to the HTACCESS located in my WordPress installation, but I can edit or change the HTACCESS file in my root on my server. Proceeding with editing my HTACCESS file in my servers root. The article calls to add this to the HTACCESS file;

RewriteRule ^login$ http://YOUR_SITE.com/wp-login.php [NC,L]

Obviously changing the code to what and placing the code you see above in the beginning of my HTACCESS file was required, doing this and changing to http://<mysite.com>/c_login.php [NC,L]. I was expecting to see the WordPress login screen, instead I got access denied ?

I know there are a few tutorials on the web for solving this, I can't give my opinion because I might mis-guide you... but I recommend using a plug-in if you want to customize. Remember, in Wordpress you want less coding so do your best to stay away from the editor. :)
Tell me if this helped

I want to code it in, I know there are plug-ins, but what is going wrong that it's not working ?

I thinks the problem basically in plug ins....

I got it working, without plug-ins :) If I could only master programming, sigh !